Outboard motor and watercraft including the same

Abstract

An outboard motor includes a left bank and a right bank. An exhaust port in each of the left bank and the right bank is arranged outward relative to a cylinder axis line in an outer motor width direction. A left exhaust pipe is arranged outward relative to a crankcase and the left bank in the outer motor width direction. A right exhaust pipe is arranged outward relative to the crankcase and the right bank in the outer motor width direction. A catalyst is located in each of the left and right exhaust pipes.

What is claimed is: 
     
       1. An outboard motor comprising:
 a V-shaped 4-cycle engine including:
 a crankshaft extending in a vertical direction; 
 a left bank extending in an obliquely rearward and leftward direction which includes a cylinder having a cylinder axis line extending in an obliquely rearward and leftward direction; and 
 a right bank extends in an obliquely rearward and rightward direction which includes a cylinder having a cylinder axis line extending in an obliquely rearward and rightward direction; wherein 
 the left bank and the right bank each include:
 a cylinder block including the cylinder provided therein; and 
 a cylinder head secured to the cylinder block so as to cover the cylinder along the cylinder axis line and defining a combustion chamber together with the cylinder, the cylinder head including an intake port arranged inward relative to the cylinder axis line in an outboard motor width direction and in communication with the combustion chamber and also including an exhaust port arranged outward relative to the cylinder axis line in the outboard motor width direction and in communication with the combustion chamber; and 
 
 
 the outboard motor further comprises:
 a crankcase including the crankshaft accommodated therein; 
 a left exhaust path arranged outward relative to the crankcase and the left bank in the outboard motor width direction and in communication with the exhaust port in the left bank; 
 a right exhaust path arranged outward relative to the crankcase and the right bank in the outboard motor width direction and in communication with the exhaust port in the right bank; 
 a left catalyst located inside the left exhaust path; and 
 a right catalyst located inside the right exhaust path. 
 
 
     
     
       2. The outboard motor according to  claim 1 , further comprising:
 a cowling including a left wall extending in an obliquely forward and rightward direction in an area outward relative to the crankcase and the cylinder block in the left bank in the outboard motor width direction, and a right wall extending in an obliquely forward and leftward direction in an area outward relative to the crankcase and the cylinder block in the right bank in the outboard motor width direction, the cowling being arranged to cover the engine; and 
 as seen in a plan view, the left and right catalysts are respectively located in an area enclosed by the crankcase, the cylinder block in the left bank, and the left wall, and an area enclosed by the crankcase, the cylinder block in the right bank, and the right wall. 
 
     
     
       3. The outboard motor according to  claim 1 , wherein, as seen in a plan view, a left end of the left exhaust path is not located to the left of a left end of the cylinder head in the left bank, and a right end of the right exhaust path is not located to the right of a right end of the cylinder head in the right bank. 
     
     
       4. The outboard motor according to  claim 1 , wherein a front end of each of the left and right catalysts is located forward with respect to a center of the crankshaft. 
     
     
       5. The outboard motor according to  claim 1 , wherein a center of each of the left and right catalysts is located forward with respect to a rear end of the corresponding cylinder block. 
     
     
       6. The outboard motor according to  claim 4 , wherein a center of each of the left and right catalysts is located rearward relative to the center of the crankshaft. 
     
     
       7. The outboard motor according to  claim 3 , further comprising an oil filter located in, as seen in a plan view, an area enclosed by the crankcase, the left exhaust path, and the left wall of the cowling or an area enclosed by the crankcase, the right exhaust path, and the right wall of the cowling. 
     
     
       8. The outboard motor according to  claim 3 , further comprising a starter motor located in, as seen in a plan view, an area enclosed by the crankcase, the left exhaust path, and the left wall of the cowling or an area enclosed by the crankcase, the right exhaust path, and the right wall of the cowling. 
     
     
       9. The outboard motor according to  claim 3 , further comprising an oil filter and a starter motor, wherein, as seen in a plan view, the oil filter and the starter motor are respectively located, or the starter motor and the oil filter are respectively located in an area enclosed by the crankcase, the left exhaust path, and the left wall of the cowling, and an area enclosed by the crankcase, the right exhaust path, and the right wall of the cowling. 
     
     
       10. The outboard motor according to  claim 1 , wherein:
 the engine includes fuel injection devices that inject fuel into the combustion chambers or the intake ports, and a fuel path connected to the fuel injection devices; and 
 a portion of the fuel path passes below the left exhaust path or the right exhaust path. 
 
     
     
       11. The outboard motor according to  claim 1 , wherein:
 the engine includes fuel injection devices that inject fuel into the combustion chambers or the intake ports, and a fuel path connected to the fuel injection devices; and 
 a portion of the fuel path passes above the left exhaust path or the right exhaust path. 
 
     
     
       12. The outboard motor according to  claim 1 , wherein the engine includes:
 fuel injection devices located rearward relative to the crankshaft to inject fuel into the combustion chambers or the intake ports; 
 a vapor separator tank including a fuel pump to transport fuel, the vapor separator tank being located forward with respect to the crankshaft; and 
 a fuel path arranged to connect the vapor separator tank and the fuel injection devices to each other; and 
 a portion of the fuel path passes below the left exhaust path or the right exhaust path. 
 
     
     
       13. The outboard motor according to  claim 1 , wherein the engine includes:
 fuel injection devices located rearward relative to the crankshaft to inject fuel into the combustion chambers or the intake ports; 
 a vapor separator tank including a fuel pump to transport fuel, the vapor separator tank being located forward with respect to the crankshaft; and 
 a fuel path arranged to connect the vapor separator tank and the fuel injection devices to each other; and 
 a portion of the fuel path passes above the left exhaust path or the right exhaust path. 
 
     
     
       14. The outboard motor according to  claim 1 , wherein:
 the left exhaust path includes a left exhaust pipe including the left catalyst accommodated therein and the right exhaust path includes a right exhaust pipe including the right catalyst accommodated therein; 
 each of the exhaust pipes includes a plurality of tube forming members which are joined to each other, the plurality of tube forming members being obtained as a result of dividing the exhaust pipe along a cross-section including a tube axis direction or a cross-section parallel or substantially parallel to the tube axis direction; and 
 at least one of the tube forming members defines an integral unitary member with the cylinder block. 
 
     
     
       15. The outboard motor according to  claim 1 , wherein:
 the left bank and the right bank each include a plurality of sets of the cylinder, the combustion chamber, the intake port, and the exhaust port; 
 the cylinders in each of the left bank and the right bank are arranged in a vertical direction; 
 an exhaust manifold is provided in the cylinder head in each of the left bank and the right bank, in communication with the plurality of exhaust ports, and integrated with the corresponding cylinder head; 
 each cylinder block and the corresponding cylinder head each include a first joining surface defined by a vertical plane perpendicular or substantially perpendicular to the cylinder axis line, and the cylinder block and the cylinder head are joined to each other such that the first joining surfaces face each other; 
 the exhaust path includes an exhaust path which includes a second joining surface inclined with respect to a vertical plane perpendicular or substantially perpendicular to the cylinder axis line and is joined to the exhaust manifold such that the second joining surface faces the exhaust manifold; and 
 the second joining surface is located closer to the cylinder head than the first joining surfaces are. 
 
     
     
       16. The outboard motor according to  claim 1 , wherein:
 the left bank and the right bank each include a plurality of sets of the cylinder, the combustion chamber, the intake port, and the exhaust port; 
 the cylinders in each of the left bank and the right bank are arranged in a vertical direction; 
 an exhaust manifold is provided in the cylinder head in each of the left bank and the right bank, the exhaust manifold being arranged to communicate with the plurality of exhaust ports and causing exhaust gas to flow upward; and 
 the exhaust path includes an exhaust pipe which includes a joining surface defined by a horizontal plane and is joined to the exhaust manifold such that the joining surface faces the exhaust manifold. 
 
     
     
       17. A watercraft comprising:
 an outboard motor according to  claim 1 . 
 
     
     
       18. A watercraft comprising:
 a plurality of the outboard motors according to  claim 1 , wherein the plurality of outboard motors are arranged side by side in an outboard motor width direction.